1. Field of the Invention
The invention relates generally to pump control systems and, more specifically, to a pump control system for an implantable blood pump.
2. Description of Related Art
Implantable blood pump systems are generally employed either to completely replace a human heart that is not functioning properly, or to boost blood circulation in patients whose heart still functions but is not pumping blood at an adequate rate. Known implantable blood pump systems are primarily used as a "bridge to transplant." In other words, existing blood pump system applications are mainly temporary fixes, intended to keep a patient alive until a donor is available. However, the shortage of human organ donors, coupled with improvements in blood pump reliability make long-term, or even permanent blood pump implementations a reality. The estimated need for a relatively simple, long-term ventricle assist device (VAD) is presently projected at between 50,000 and 100,000 patients per year in the United States alone.
Despite this need, existing implantable pump systems have not been satisfactory for long term use. Known systems of the continuous flow type are designed primarily for use in a hospital setting. These systems typically include the implanted pump device, a power source such as a rechargeable battery, a motor controller for operating the pump motor, and an external operator console. While some existing implantable pump systems allow for operation while decoupled from the operator console, operating these systems "stand-alone" can be a risky endeavor. This is due, at least in part, to the lack of an adequate user interface when the system is decoupled from the console.
Prior art blood pump systems generally only include electronics for operating the pump when disconnected from the console. Often, the user interface is limited to a green light indicating that the system is operating, or a red light indicating that the system is not operating properly. There are no provisions for displaying system parameters, diagnostic messages, alarm messages, etc. Further, known systems typically lack memory capabilities. Hence, when a technician attempts to diagnose a prior art blood pump system after the red light indicated a system failure, there is no record of the system conditions related to the failure.
Further, even when an implantable continuous flow pump is coupled to an operator console, relevant system parameters are missing. For example, the operator consoles of known continuous flow pump systems may monitor pump parameters such as voltage level, current level, pump speed, etc. These parameters, however, do not provide all the necessary information to properly monitor a system that is as complicated as the human circulatory system. The system can be better assessed if pump parameters are analyzed in conjunction with other factors, such as blood flow rate, blood pressure or vibro-acoustic signatures. It is even more desirable to monitor all of these parameters together in real time. Unfortunately, known blood pump systems typically lack the ability to integrally analyze these data in real time.
Moreover, prior blood pump systems are not conducive to long-term use outside an institutional setting. As discussed above, known systems require a large, fixed operator console for the system to function. While prior art operator consoles may be cart mounted to be wheeled about the hospital, at home use of known systems is difficult at best.
Other problems of prior pump systems that have limited their mobility and use to relatively short times are related to motor controller size and shape limitations necessary for convenient mobility, weight limitations for implantation to avoid tearing of implant grafts due to inertia of sudden movement, high power consumption that requires a larger power supply, complex Hall Effect sensors/electronics for rotary control, the substantial desire for minimizing percutaneous (through the skin) insertions, including support lines and tubes, and high cost effectively.
Thus, there is a need for an implantable pump control system that addresses the shortcomings associated with the prior art.